From dcfd5c2c2cefcd8ae6a5b2e90fcbd98da4f1b120 Mon Sep 17 00:00:00 2001
From: Hugo Herbelin
Date: Sat, 25 Nov 2017 20:50:03 +0100
Subject: Notations: Adding modifiers to tell which kind of binder a constr can
 parse.

Concretely, we provide "constr as ident", "constr as strict pattern"
and "constr as pattern".

This tells to parse a binder as a constr, restricting to only ident or
to only a strict pattern, or to a pattern which can also be an ident.

The "strict pattern" modifier allows to restrict the use of patterns
in printing rules. This allows e.g. to select the appropriate rule for
printing between {x|P} and {'pat|P}.
---
 parsing/g_vernac.ml4 | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

(limited to 'parsing')

diff --git a/parsing/g_vernac.ml4 b/parsing/g_vernac.ml4
index 009c1c19a6..cca1b29898 100644
--- a/parsing/g_vernac.ml4
+++ b/parsing/g_vernac.ml4
@@ -1174,6 +1174,7 @@ GEXTEND Gram
       | x = IDENT; ","; l = LIST1 [id = IDENT -> id ] SEP ","; "at";
         lev = level -> SetItemLevel (x::l,lev)
       | x = IDENT; "at"; lev = level -> SetItemLevel ([x],lev)
+      | x = IDENT; "at"; lev = level; b = constr_as_binder_kind -> SetItemLevelAsBinder ([x],b,lev)
       | x = IDENT; typ = syntax_extension_type -> SetEntryType (x,typ)
     ] ]
   ;
@@ -1181,9 +1182,20 @@ GEXTEND Gram
     [ [ IDENT "ident" -> ETName | IDENT "global" -> ETReference
       | IDENT "bigint" -> ETBigint
       | IDENT "binder" -> ETBinder true
-      | IDENT "pattern" -> ETPattern None
-      | IDENT "pattern"; "at"; IDENT "level"; n = natural -> ETPattern (Some n)
+      | IDENT "constr"; n = OPT at_level; b = constr_as_binder_kind -> ETConstrAsBinder (b,n)
+      | IDENT "pattern" -> ETPattern (false,None)
+      | IDENT "pattern"; "at"; IDENT "level"; n = natural -> ETPattern (false,Some n)
+      | IDENT "strict"; IDENT "pattern" -> ETPattern (true,None)
+      | IDENT "strict"; IDENT "pattern"; "at"; IDENT "level"; n = natural -> ETPattern (true,Some n)
       | IDENT "closed"; IDENT "binder" -> ETBinder false
     ] ]
   ;
+  at_level:
+    [ [ "at"; n = level -> n ] ]
+  ;
+  constr_as_binder_kind:
+    [ [ "as"; IDENT "ident" -> AsIdent
+      | "as"; IDENT "pattern" -> AsIdentOrPattern
+      | "as"; IDENT "strict"; IDENT "pattern" -> AsStrictPattern ] ]
+  ;
 END
-- 
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